Small unmanned ground vehicle

ABSTRACT

The present teachings relate generally to a small remote vehicle having rotatable flippers and a weight of less than about 10 pounds and that can climb a conventional-sized stairs. The present teachings also relate to a small remote vehicle can be thrown or dropped fifteen feet onto a hard/inelastic surface without incurring structural damage that may impede its mission. The present teachings further relate to a small remote vehicle having a weight of less than about 10 pounds and a power source supporting missions of at least 6 hours.

This U.S. patent application is a continuation of U.S. patentapplication Ser. No. 13/342,022, filed Dec. 31, 2011, which claimspriority to U.S. Provisional Patent Application No. 61/442,790, filedFeb. 14, 2011, for Small Unmanned Ground Vehicle, and claims priority toU.S. Provisional Patent Application No. 61/436,994, filed Jan. 27, 2011,for Resilient Wheel Assemblies, the entire content of all applicationsare incorporated herein by reference in their entireties.

The present teachings relate generally to a small unmanned groundvehicle. The present teachings relate more particularly to a smallunmanned ground vehicle weighing less than about five pounds, and whichis designed to absorb an impact from being dropped or thrown and climbstairs of a conventional size.

BACKGROUND

The section headings used herein are for organizational purposes onlyand are not to be construed as limiting the subject matter described inany way.

In military and industrial settings, personnel often encounter dangeroussituations where intelligence of what lies ahead could save lives.Dismounted military patrols can use a lightweight, portable robot tomaneuver into small spaces prone to ambush, and inspect potentialthreats, including suspected improvised explosive devices (IEDs). Asmall search robot can also be used to assess situations before exposingpersonnel to harm. In industrial settings, emergency personnel canpre-position or insert a small inspection robot in hazardous spaces toevaluate the situation before humans enter the area. Such a robot canevaluate the extent of danger before rescue teams enter sealed areas inmining operations, chemical plants, or nuclear reactors.

SUMMARY

The present teachings may solve one or more of the above-mentionedproblems and/or achieve one or more of the above-mentioned desirablefeatures. Other features and/or advantages may become apparent from thedescription which follows.

A robot in accordance with embodiments of the present teachings cancomprise a lightweight, man-portable search robot designed to help keepmilitary personnel and industrial personnel out of harm's way. It can bedeployable and extremely maneuverable, and can serve as aforward-looking eye that travels ahead of dismounted military forces orindustrial emergency personnel. Embodiments of the robot can alsoindicate the presence of IEDs, enemy combatants, and other potentialhazards.

The present teachings additionally provide for a mobile robot having achassis volume. A battery housed within the chassis comprises a batteryvolume, the battery being configured to support intended missions of themobile robot for at least 6 hours, the intended missions including atleast driving the mobile robot and powering a radio thereon. A drivensupport surface can be movably connected to each side of the chassis andconfigured to propel the chassis in at least a forward direction, eachdriven support surface comprising a flexible track trained about a pairof wheels. A flipper rotatably can be connected to each side of thechassis rearward of the center of gravity of the chassis, the flippersbeing configured to rotate in a first direction to raise the rearwardend of the robot and to rotate in a second and opposite direction toraise the forward end of the robot chassis, and the battery volume canbe at least about 10 percent of the total volume of the chassis.

The present teachings additionally provide for a mobile robot comprisinga chassis having a forward end, a rearward end, and a center of gravity.A driven support surface is movably connected to each side of thechassis and configured to propel the chassis in at least a forwarddirection, each driven support surface comprising a flexible tracktrained about a pair of wheels. A flipper is rotatably connected to eachside of the chassis rearward of the center of gravity of the chassis,the flippers being configured to rotate in a first direction to raisethe rearward end of the robot and to rotate in a second and oppositedirection to raise the forward end of the robot chassis. A sensorlocated on a side of the chassis and has a field of view in a directionsubstantially parallel to the ground through a respective track. Theflipper has a transparent portion configured to prevent the flipper fromblocking at least a portion of the field of sensing of the sensor.

The present teachings additionally provide for a mobile robot comprisinga chassis having a top surface, a bottom surface, side surfaces, a frontsurface and a rear surface. A battery is housed within the chassis andincluding two or more cylindrical cells, the battery resting on a bottomsurface of the housing. A driven support surface is movably connected toeach side of the chassis and configured to propel the chassis in atleast a forward direction, each driven support surface comprising aflexible track trained about a pair of wheels. A flipper is rotatablyconnected to each side of the chassis rearward of the center of gravityof the chassis, the flippers being configured to rotate in a firstdirection to raise the rearward end of the robot and to rotate in asecond and opposite direction to raise the forward end of the robotchassis, wherein the bottom surface of the housing is contoured toaccommodate a shape of the battery cells and is configured to conductheat away from the battery by providing additional surface area for heatdissipation.

The present teachings additionally provide for a mobile robot configuredcomprising a chassis having a forward end, a rearward end, and a centerof gravity. A driven support surface is movably connected to each sideof the chassis and configured to propel the chassis in at least aforward direction, each driven support surface comprising a flexibletrack trained about a pair of wheels, each longitudinal support surfacehaving a front end and a rear end, a longitudinal length from the frontend to the rear end. A flipper is rotatably connected to each side ofthe chassis rearward of the center of gravity of the chassis, theflippers being configured to rotate in a first direction to raise therearward end of the robot and to rotate in a second and oppositedirection to raise the forward end of the robot chassis. The mobilerobot further comprises a flipper motor, to provide a rotational forceto rotate the flipper, and a flipper drive gear, to translate therotational force from the flipper motor to the flipper.

The present teachings additionally provide for a mobile robot system,comprising a mobile robot and an operator control unit to communicatewith the mobile robot. The mobile robot comprises a chassis having aforward end, a rearward end, and a center of gravity; an antennaextending in an upward direction from a top surface of the chassis, theantenna configured to bend for stowage and resiliently return to anupright position when released from stowage, to transmit and receivesignals; a driven support surface movably connected to each side of thechassis and configured to propel the chassis in at least a forwarddirection, each driven support surface comprising a flexible tracktrained about a pair of wheels, each longitudinal support surface havinga front end and a rear end, a longitudinal length from the front end tothe rear end; a flipper rotatably connected to each side of the chassisrearward of the center of gravity of the chassis, the flippers beingconfigured to rotate in a first direction to raise the rearward end ofthe robot and to rotate in a second and opposite direction to raise theforward end of the robot chassis; and a plurality of sensors disposedalong an exterior surface of the chassis. The operator control unitfurther comprises a housing; an antenna, supported by the housing, totransmit to and receive signals from the mobile robot; a display, toprovide information regarding the operation of the mobile robot; and aninput device, coupled to the display, to receive input to the operatorcontrol unit to issue instructions to the mobile robot.

The present teachings additionally provide for a mobile robot systemcomprising a mobile robot, an operator control unit to communicate withthe mobile robot, and a docking station. The mobile robot comprises achassis having a forward end, a rearward end, and a center of gravity;an antenna extending in an upward direction from a top surface of thechassis, the antenna configured to bend for stowage and resilientlyreturn to an upright position when released from stowage, to transmitand receive signals; a driven support surface movably connected to eachside of the chassis and configured to propel the chassis in at least aforward direction, each driven support surface comprising a flexibletrack trained about a pair of wheels, each longitudinal support surfacehaving a front end and a rear end, a longitudinal length from the frontend to the rear end; a flipper rotatably connected to each side of thechassis rearward of the center of gravity of the chassis, the flippersbeing configured to rotate in a first direction to raise the rearwardend of the robot and to rotate in a second and opposite direction toraise the forward end of the robot chassis; and a plurality of sensorsdisposed along an exterior surface of the chassis. The operator controlunit comprises a housing; an antenna, supported by the housing, totransmit to and receive signals from the mobile robot; a display, toprovide information regarding the operation of the mobile robot; and aninput device, coupled to the display, to receive input to the operatorcontrol unit to issue instructions to the mobile robot. The dockingstation comprises a first portion to accommodate the mobile robot, and asecond portion to accommodate the operator control unit, where the robotsystem can be transported by use of the docking station when the mobilerobot and the operator control unit are accommodated into the first andsecond portions, respectively.

Additional objects and advantages of the present teachings will be setforth in part, in the description which follows, and in part will beobvious from the description, or may be learned by practice of thepresent teachings. The objects and advantages of the present teachingscan be realized and attained by means of the elements and combinationsparticularly pointed out in the appended claims.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the present teachings, as claimed.

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate exemplary embodiments of thepresent teachings and together with the description, serve to explainthe principles of those teachings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side perspective view of an exemplary embodiment of a robotin accordance with the present teachings.

FIG. 2 is a side view of the embodiment of FIG. 1.

FIG. 3 is a perspective view of an exemplary embodiment of a flipperstructure in accordance with the present teachings

FIG. 4 is a side perspective view of the embodiment of FIG. 1, with thecover, antenna, left flipper, left wheels, and left track removed.

FIG. 5 is a top perspective view of the embodiment of FIG. 1, showingthe cover, antenna, certain internal elements like printed circuitboards (PCBs) and the battery, left flipper, left wheels, and left trackremoved.

FIG. 6 illustrates an embodiment of a flipper clutch for a robot inaccordance with the present teachings.

FIG. 7 illustrates the flipper clutch gear of FIG. 6.

FIG. 8 is a cross sectional view of the robot of FIG. 1, taken throughthe drive gears and looking toward a front of the robot.

FIG. 9 is a cross sectional view of the robot of FIG. 1, taken throughthe front axle and looking toward a rear of the robot.

FIG. 10 is a cross sectional view of the robot of FIG. 1, taken throughthe side cameras and looking toward a rear of the robot.

FIG. 11 is a cross sectional view of the robot of FIG. 1, taken throughthe rear axle and looking toward a rear of the robot.

FIG. 12 is a cross sectional view of the robot of FIG. 1, taken througha portion of the right-side drive gear assembly and looking toward aright side of the robot.

FIG. 13 is a cross sectional view of the robot of FIG. 1, taken midwaythrough the robot and looking toward a right side of the robot.

FIG. 14 is an exemplary robot system diagram.

FIGS. 15A-15B illustrate two exemplary communication PCB diagrams.

FIG. 16 is an exemplary infrared (IR) sensor diagram.

FIG. 17 is an exemplary camera PCB diagram.

FIGS. 18A-18B illustrate an exemplary power system diagram.

FIG. 19 illustrates an exemplary interconnection of robot PCBs.

FIGS. 20-21 illustrate exemplary embodiments of a handheld controllerfor controlling a robot in accordance with the present teachings,including some exemplary measurements in millimeters.

FIGS. 22-23 illustrate the handheld controllers of FIGS. 20-21 includingan additional exemplary measurement in millimeters.

FIG. 24 is a side view of the handheld controller of FIG. 20.

FIG. 25 is a side view of the handheld controller of FIG. 20, with thecase being transparent.

FIG. 26 is a top perspective view of the handheld controller of FIG. 20,with the cover and screen removed.

FIG. 27 is a side perspective view of another embodiment of a controllerthat can be attached to an operator's wrists using one or more straps.

FIG. 28 is a side perspective view of the controller of FIG. 27, withthe top cover removed.

FIG. 29 is a side perspective view of the controller of FIG. 27, withthe top cover and display screen removed.

FIG. 30 is a cross sectional view of the controller of FIG. 27.

FIG. 31 is another cross sectional view of the controller of FIG. 27.

FIG. 32 is an embodiment of an operator control unit (OCU) systemdiagram.

FIG. 33 is a system diagram for an embodiment of a robot docking stationand charger.

FIG. 34 is a system diagram for another embodiment of a robot dockingstation and charger.

FIGS. 35-36 illustrate a robot system with an exemplary storage/chargingdock.

FIG. 37 illustrates exemplary general specifications in embodiments ofthe present teachings.

DESCRIPTION

Reference will now be made in detail to exemplary embodiments of thepresent teachings, examples of which are illustrated in the accompanyingdrawings.

The present teachings contemplate a small remote vehicle system,embodied herein for exemplary purposes as a small robot. In anembodiment, the small robot can have a mass of approximately 4 pounds,and can be, for example, about 10″ in length×9″ in width×4″ in height(e.g., without consideration of an extended antenna height). Embodimentsof the small robot can include a radio with a 200 meter range and whichcan function in a designated frequency range or designated frequencyranges, for example 2.4 GHz, 5.4 GHZ, or 4.5 GHz. In certain embodimentsof the present teachings, the radio can be compatible with CREW (CounterRadio-controlled improvised explosive devices (RCIED) ElectronicWarfare) program specifications. The present teachings also contemplatethe use of optional encryption schemes. The radio can be two-way toprovide situational awareness.

In various embodiments of the present teachings, the robot can beruggedized, for example, to withstand a fall from a height of greaterthan 3 meters, to tumble down stairs, and/or to be waterproof. The robotcan exhibit excellent mobility characteristics including the ability toclimb 8″ obstacles and to maneuver in common urban terrain, includingnavigation of stairs, curbs, and gravel. The robot system can be capableof ground speeds of greater than 1.5 m/s (5.4 kph) using wheels, treads,tracks, or other propulsion devices. In certain embodiments, along-lasting power supply and energy conservation capabilities canprovide up to 11 km driving distance, and/or up to 8 hours performancein a surveillance mode.

Embodiments of the robot system can include cameras, infrared (IR)illuminators, and sensors to provide situational awareness. When usedwith a two-way radio or other communication capability, the robot systemcan provide a user with extended situational awareness. In certainembodiments of the present teachings, an operator control unit (OCU) canprovide wireless command and control over the robot system, which can behighly portable and ruggedized for, for example, combat scenarios.Embodiments of the OCU can include a touchscreen or other input device,and can further provided a device to allow attachment of the OCU to anoperator's wrist. The robot system can also be configured to communicatewith other robot systems, including the capability of forming ad-hoccommunication networks, including mesh networking and “bucket brigade”(i.e., daisy chained communication) to extend a communication rangethrough use of a plurality of robot systems. The robot system canfurther be configured to perform a variety of behaviors autonomously orsemi-autonomously, including self-righting, step climbing, cliffavoidance, wall and obstacle avoidance and navigation, wall following,and retro-traverse behaviors. A plurality of robot systems can alsoperform maneuvers cooperatively, to accomplish tasks a single robotsystem would be unable to perform. For example, one or more robots inaccordance with the present teachings can be interoperable with anentire fleet of robots controllers allowing one operator to control manyrobots. Interoperability can enable cooperative and marsupial missionsinvolving heterogeneous robot platforms using, for example, an advancebehavior engine such as iRobot's® Aware® 2 Robot Intelligence Softwaretechnology. Robot interoperability can facilitate providingcost-effective, multi-robot systems that can adapt to a wide variety ofreal-world challenges. An example of general specifications of a smallrobot in accordance with embodiments of the present teachings isillustrated in FIG. 33.

FIGS. 35 and 36 illustrate a robot system with an exemplarystorage/charging dock in accordance with the present teachings which cancomprise, for example, a robot 3202 and charging dock equipment 3204. Inembodiments, an operator control system (not illustrated in FIGS. 35 and36) can also be included. Prior to using the robot system, batteries ofthe robot system can be charged while the robot 3202 is secured in thecharging dock equipment 3204. The robot 3202 and controller can beremoved from the charging dock and stowed in a backpack, vest-mountedpouch, or similar carrying device. The robot 3202 can remainconveniently stowed away until needed for a reconnaissance or othermission. When needed, the robot is removed from its carrying compartment3204 and activated. The robot 3202 can be a throwable robot and can betossed down a corridor, into a window, or up a stairwell. The robot canabsorb impact forces as described above and, after landing, can rightitself if necessary and be remotely operated. Video feed can beevaluated before determining the next course of action.

Using a robot in accordance with the present teachings can reducecollateral casualties by allowing military personnel to determine adegree of hostile intent before entering a dangerous environment Therobot can also look for and determine the presence of IEDs and othersafety hazards. In certain embodiments of the present teachings,utilizing several robots can extend a range of operations by acting ascommunication-relay nodes. A wider area of communication coverage can beprovided if a robot is tossed onto a roof top or other high locationswith good visibility.

For certain applications, a system in accordance with the presentteachings that includes a docking station can he permanently installedat floor level inside a containment building, where the robot can chargein its charging dock (see above) until needed to perform a mission inthe building or elsewhere. When an incident occurs, remote personnel candeploy the robot from its charging dock to evaluate, for example, theextent and type of an incident. The robot can, in certain embodiments,autonomously return to its charging dock when the mission is completed.Indeed, the present teachings contemplate a remote vehicle that can beremotely deployed from its charging station and autonomously returnthereto, requiring no on-site human intervention.

In an exemplary use, in a civilian industrial setting, a home orbuilding inspector can keep the robot in a wall-mounted charging dockinside an equipment truck until needed. When arriving on site, the robotcan be charged and ready for deployment. The inspector can remove therobot from its charging dock and deploy it for evaluation tasks,especially for tasks in areas difficult or dangerous to reach, such asunder-house or storm drainage system inspection. After use, the robotcan be returned to its charging dock.

Various embodiments of a system in accordance with the presentteachings, including training documentation, can fit into a small boxweighing less than ten pounds, and can be easily shipped. Optionally,the system can be shipped or carried in, for example, a ruggedwaterproof case, commonly referred to as a Pelican case. Certainembodiments of the robot have a small form factor with two tracks,similar to a small tank. The robot preferably has side flippers, whichin certain embodiments can rotate 360° around their axles to assist therobot in stair climbing, obstacle surmounting, self-righting, andcertain other behaviors.

In various embodiments of the present teachings, the robot can climbstairs and curbs. The robot's platform can be, for example, about 10×9×4inches, weigh about four pounds, and can be dropped fifteen feet onto ahard/inelastic surface (e.g., a concrete floor) without incurringstructural damage that may impede its mission. For power, the robot canuse, for example, built-in rechargeable lithium ion batteries, which cansupport typical mission durations of in excess of six hours. Certainembodiments of the robot can contain a small payload interface on topwhere optional sensors, manipulators, or other payloads con be attached.Certain embodiments of the robot can, for example, accommodate a payloadof up to 0.5 pound without impeded mobility, in accordance with variousembodiments, the robot's motor can provide a top speed near 1.5 m/sec(3.4 mph). Exemplary embodiments of such robots are further described inU.S. patent application Ser. No. 13/052,022, filed Mar. 18, 2011, forMOBILE ROBOT SYSTEMS AND METHODS, which is herein incorporated byreference in its entirety.

In various embodiments, the robot's primary processor system cancomprise an ARM processor, which can handle processing of commands andtelemetry (which can be, for example, JAUS/SAE AS-4 compliant),motor-control loops, video processing and compression, and assistiveautonomous behaviors implemented in an advanced behavior engine such asiRobot®'s Aware® software architecture. The robot can optionally beconfigured to be compliant and/or compatible with various robotinterface standards, including JAUS and SAE AS-4.

In certain embodiments, a set of sensors for perceiving terrain (e.g.,obstacles, cliffs and walls), inclinations, and orientation can beutilized to assist the operator with common tasks such as obstacledetection and avoidance, wall following, and cliff avoidance, relievingthe need for difficult and intensive teleoperation during such tasks asdriving in a straight line in a in a walled space and self-righting. Therobot can interoperate with other robot products and compatible operatorcontrol units (OCUs). Interoperability can allow the same OCU to operatetwo robots (of the same type or a different type) simultaneously.

In accordance with various embodiments, a small, wrist-mounted OCUincludes a radio, an antenna, and a battery capacity to accommodate therobot's mission life. The OCU can, for example, measure 6.5×4.5×2inches, weigh approximately one pound, and conveniently stow in pocketssuch as the cargo pocket of a military uniform. The OCU can, forexample, display all of the robot's real-time video streamssimultaneously, allow direct control of the robot, and allow initiationof assorted autonomous and/or semi-autonomous behaviors. The OCU canadditionally display, for example, the status of the robot's systems,including battery state of charge and flipper mechanism position. Invarious embodiments, the OCU can be weather resistant and configured tooperate, for example, over a −10° C. to 50° C. temperature range.

A robot in accordance with the present teachings is preferably a small,light-weight, tracked vehicle with trackless flippers as shown inFIG. 1. The flippers can he mounted to a rear axle of the robot, inaccordance with various embodiments, when the flippers are stowed, therobot can be, for example about the size of a large telephone book, andcan fit into an assault pack. The robot's small form factor and lightweight can lend it well to dropping throwing into restricted spaces; andno external protective device is needed to protect the robot uponlanding. The present teachings contemplate several robots being carriedin a single backpack. In various embodiments of the present teachings, asmall, ruggedized, PDA-style controller can be provided with the robot.The controller can weigh, for example, about one pound. The robot'scharging dock can, for example, fit in an assault pack with the robotand its controller.

Various robots in accordance with the present teachings provide thesmallest robot that can climb stairs, street curbs, and other obstaclescommon in urban environments. Such climbing is accomplished with theflippers as shown and described above. Embodiments of the robot canhave, as illustrated herein, four wheels, rubber elastic tracks, and aflat brick-shaped body. The flippers are capable of continuous360-degree rotation in both directions. The flippers can self-right therobot if it inverts, and can help the robot to overcome a wide varietyof obstacles that typically obstruct a small robot. Such robots arefurther described in the aforementioned U.S. patent application Ser. No.13/052,022, which is incorporated by reference herein in its entirety.

Certain embodiments of robot systems in accordance with the presentteachings can climb stairs and crawl over rough terrain without gettingstuck in rubble and debris. Certain embodiments of the robot can climb60° slopes, and traverse 45° slopes. In various embodiments, theflippers can help the robot cross gaps over six inches in length. Thetracked drive train can, in some embodiments, move the robot at speedsin excess of 1.5 meters/sec. The flipper system provides a high degreeof mobility. The flippers' 360-degree rotation allows the robot to“swim” over rubble piles and rugged terrain that typically stop smallrobots with low ground clearance. The flippers can also self-right therobot when it is thrown or dropped onto a hard surface. Theflipper-based self-righting feature allows the robot to self right evenwhen its radio antennas and payloads such as sensors are designed intothe top of the robot for appropriate visibility. The ability to positionpayloads and antennas on top of the robot is not available on existinginvertible robot systems that do not have flippers.

Various embodiments of a robot in accordance with the present teachingsare waterproof to IP67, and operate over a wide temperature range. Therobot's low form factor can make it resistant to very high winds, inexcess of 45 mph, with little degradation of mission performance. Asstated above, embodiments of the robot can operate in temperaturesranging from −10° C to 60° C., with the operational temperature rangebeing largely dictated by current lithium ion battery technology.

In certain embodiments, video is provided through four smallmulti-megapixel cameras built into the robot. Each camera can be pointedin a cardinal direction (front, back, left, and right) to allow fullsituational awareness, and can have a sufficient field of view to ensurefull situational awareness. In certain embodiments, the operator candigitally pan-tilt and zoom within this field of view, take snapshots,and records videos for purposes of collecting intelligence data. Thecameras preferably tolerate full sun, and do not wash out images. Forlow-light or night operations, an IR illumination array can be utilizedto provide sufficient illumination to operate in typical urbansituations.

In certain embodiments, to preserve true daylight colors, the cameralenses can have infrared (IR) cut filters with a notch band for thespecific wavelength of the IR illumination. This can eliminate mostambient daylight IR light, preventing the washed out colors common inlenses with IR cut filters removed.

In various embodiments, the batteries can support over two hours ofcontinuous, full-speed driving, or up to 10 hours of stationaryobservation, while transmitting full-motion video. In an embodiment,each battery can include one or more metal ion rechargeable batteries,for example, eight cells in a two-parallel, four-series configurationof, for example, 18650 cell-style lithium ion batteries. In variousembodiments, a battery stack can be built into the robot, allowing therobot to be smaller, lighter, more rugged, and cheaper to build withfewer potential leak points than with a user-replaceable battery pack. Abuilt-in battery design can eliminate duplicate bulkheads and seals thatare typically needed for a user-replaceable battery compartment. Thesmall size and light weight of lithium ion batteries allow the robot tobe shipped by common air carrier without special hazardous materialspackaging. For example, embodiments of the robot with eight Li-ion cellscontain less than eight total grams of lithium.

The robot charging dock can utilize a continuously-available powersource such as, for example, a wall socket electrical supply in therange of 110-250V AC 50-60 Hz. The robot can also operate using anoptional 12-28 VDC charger. The small size and low cost of the robotwill allow personnel to carry spare robots instead of spare batteries,if extended mission runtime is expected.

The robot's radio can comprise, for example, a USB module, and cansupport bi-directional digital communication and mobile ad hoc meshnetworking. The default radio can operate on a frequency of 5.8 GHz, andhave a line-of-sight range in excess of 200 meters. The radio can alsosupport operations on 2.4 GHz, or can be replaced to support a widervariety of frequencies. The robot can optionally be equipped with aradio supporting a military band of 4.475-4.725 GHz with 200 m range.The radio can be connected to a flexible antenna mounted on top of therobot with a unique collapsible mast such as the mast disclosed in U.S.patent application Ser. No. 13/340,456, filed Dec. 29, 2011, for AntennaSupport Structure, the entire disclosure of which is incorporated byreference herein. When the robot flips over or onto its side, autonomousself-righting behavior self-rights the robot to allow such a flexibleantenna to regain its upright position. The radio can comprise, forexample, a bi-directional 802.11 class radio relying on greater than a900 MHz bandwidth.

In accordance with certain aspects of the present teachings, in areaswhere RF performance may be degraded by background noise, or obstructedby terrain, several robots can be used together as relay nodes to extendthe operational range. If the first robot reaches its RF communicationslimit, a second robot can be deployed to drive past the first robot intoan inaccessible area, utilizing the first robot as a radio-relay node.The mesh networking capability can be built into some embodiments of therobot.

In certain embodiments, sensors on the robot can measure, for example:battery state of charge; voltage; amperage; tilt/inclination and bumpsensing; cliff detection; wall following; yaw-angular rate to detectslippage and enhance odometry; motor currents; and flipper position. Therobot can have on-board logging of diagnostic data, and can warn theoperator of potential impending system failures requiring maintenance.The robot's autonomous capabilities can include, for example, one ormore of the following.

Self-righting—a built-in, autonomous, self-righting behavior. When therobot is on and left undisturbed in an inverted position, the flippersactivate in a series of maneuvers to upright the robot to ensure thatthe robot is returned to the upright position.

Step climbing—the robot can climb steps, preferably almost as deep asits size. However, the sequence of events that needs to occur tosuccessfully surmount a large step is not trivial to perform when themotors are directly controlled by the operator. To facilitate stepclimbing, the robot can have a built-in assistive behavior initiated bythe remote operator once the robot is positioned in front of the step.The assistive behavior executes the sequence of motions required toclimb the step based upon the feedback from appropriate internalsensors. Further examples of such step climbing can be found in theaforementioned U.S. patent application Ser. No. 13/052,022.

Cliff detection—due to the low perspective of the robot's cameras, it isoften difficult for an operator to see when the robot is driving towardsa drop off, such as the top of a flight of stairs or the edge of aplatform. To assist the operator in such situations, the robot can havebuilt-in cliff sensors that are utilized in a protected driving mode. Ifthe operator drives the robot too close to the edge of a stairwell orcliff, the robot stops, and can verify that the operator is aware of thedrop off by projecting a warning message on the OCU. The operator canthen decide to turn away from the edge, or to proceed and drive over theledge.

Wall following—to facilitate searching a room or space, the operator cancommand the robot to follow a wall clockwise or counter clockwise arounda room's perimeter. The robot autonomously drives around the perimeterhugging the base of the wall.

Video Guard Mode—the robot can be configured in a low-power, standbymode. In this mode, the robot wakes up and transmits an alert if it seesany motion. This mode can be useful when securing an area in aleave-behind scenario.

Certain embodiments of the robot can contain an expansion port for theaddition of future payload modules where optional sensors, manipulators,or destructive payloads are attached. The robot can, for example,accommodate a payload of up to 0.5 pound without impeded mobility.Payload expansion can allow integration of specialized cameras andsensors, including thermal imagers, chem-bio-radiation sensors, anddestructive payloads.

FIG. 1 is a side perspective view of an exemplary embodiment, of a robot100 in accordance with the present teachings. As shown, the robot 100includes a housing 102 having wheels 106, 118, 130 and 136 on each sidethereof and tracks 104, 138 spanning a front wheel and a rear wheel. Thehousing 102 can comprise, for example, aluminum or another suitablydurable material including other metals, plastics, composites, etc.Flippers 110 can be provided, for example, attached directly orindirectly to a rear axle 142 of the vehicle (i.e., a rear axle spanningwheels 106 and 136), and can be rotatable, for example through 360degrees, about the rear axle 142. The flippers 110 can be made from asuitably rugged material to withstand impacts that the robot may incurin use, and can be suitably strong to lift the weight of the robot andany payloads or accessories attached thereto. The flippers 110 canextend, for example, from rear axle 142 (at the flippers' proximal ends)to front axle 144 (at the flippers' distal ends), and can be tapered tobe wider at their proximal ends and thinner at their distal ends. Thedistal end can be, for example, rounded as illustrated. The flippers 110preferably extend generally parallel to a side of the robot when in astored state and spaced from the robot a distance that preventsinterference of the flipper with a motion of the robot or otheroperations of the robot while also preventing the flipper from catchingon objects in the robot's environment. Flippers 110 can be mounted tothe rear wheel assembly via, for example, a four-bar linkage 108 that isfurther described below. As will be appreciated by those of ordinaryskill in the art, the robot 108 will have a center of gravity betweenthe front axle 144 and the rear axle 142, and between tracks 104, 138.

In certain embodiments of the present teachings, a top surface 146 ofthe robot housing 102 lies slightly below the surface of the tracks 104and 138, and is substantially flat. The top surface 146 can include apayload expansion port cover 140 that can be removed to attach a payloadto the robot, but which can optionally also serve as a surface for asound exciter, as discussed in further detail below.

As illustrated in FIG. 1, an antenna assembly 148 extends upwardly froma top surface of the robot housing. The antenna assembly 148 cancomprise, for example, an antenna mast 132 and an antenna 134. Theantenna mast 132 can be, for example, bendable and resilient, and may,for example, comprise a rubber tube or an arrangement of shape memoryalloy elements. In operation, antenna mast 132 can be folded over therobot housing 102 for compact storage. Such an antenna 134, mast 132 andassembly 148 are further described in U.S. patent application Ser. No.13/340,456, filed Dec. 29, 2011, for Antenna Support Structure, theentire disclosure of which is incorporated by reference herein.

In the illustrated robot 100, many features of the robot can be designedto absorb an impact that the robot may receive if dropped or thrown. Forexample, antenna mast 132 can be bendable and resilient to absorb impactby folding. In addition, wheels 106, 118, 130 and 136 can have spiralspokes to absorb radial impact and/or slotted spokes to absorb axialimpact. The flippers, such as flipper 110, can be attached to the rearaxle 142 by a four-bar linkage 108 allowing the flipper to better absorbside impact. Such wheels and flippers are further described in U.S.patent application Ser. No. 13/340,957, filed Dec. 30, 2011, forResilient Wheel Assemblies, which is incorporated by reference herein inits entirety.

Embodiments of the robot 100 can include cameras 114, 124 on the sides,front, and/or back of the robot, the cameras 114, 124 providing anoperator with situational awareness. Each camera 114, 124 can optionallybe provided with an IR LED (e.g., an IR LED on each side of the camera)for low-light operation. Exemplary front camera 124 with IR LEDs 122 and126 and exemplary left-side camera 114 with IR LEDs 112, 116 areillustrated in FIG. 1.

The left flipper 110 in FIG. 1 is illustrated in its stowed position,such that it extends from the rear axle 142 of the robot 100 toward thefront axle 144 of the robot. In certain embodiments of the presentteachings, the flipper 110 covers the side camera 114 when in a stowedposition (see FIG. 2), which could potentially cause an operator to losesome situational awareness when the flipper rests in or passes throughthe illustrated stowed position. Such loss of situational awareness canbe substantially prevented by operating the vehicle with the flippers ina position that does not cover the side cameras. Certain embodiments ofthe present teachings contemplate providing a cutaway, hole, ortransparent portion for flipper 110, configured to prevent the flipperfrom blocking at least a portion of the field of view of the side camera114, IR LED 112, 116, and/or a wall-following sensor located adjacentthereto, thereabove, or thereunder.

The antenna mast 132 (or in some embodiments, antenna assembly 148)being bendable and resilient additionally allows the robot to driveunder objects with a clearance less than its antenna height, and performa self-righting maneuver more easily because the flippers need notovercome the height of the mast to flip the robot over. Further, theheight of the antenna assembly 148 (i.e., the height of the antenna mast132, the antenna 134, or both) can be selected to allow a desiredcommunication range with the operator control unit, which, for example,can be a 200 meter-to-300 meter range. In certain embodiments of thepresent teachings, the antenna assembly 148 can be positioned toward afront end of the robot to facilitate stair climbing, so that the weightof the antenna moves the center-of-gravity of the robot forward, helpingthe front end of the robot tip forward as, for example, it surmounts thestair riser. The size of the robot can be configured to accommodate thesize of the antenna. For example, the robot can be sized so that theantenna can rest on and be supported on a top surface 146 of the robothousing 102. In various embodiments, the top surface 146 of housing 102can be lower than the top of tracks 104 and 138 to form a gap above thetop surface 146 and between the tracks 104, 138. In such embodiments,the antenna can bend or fold to it within a gap between the top of thehousing and the tracks, so that the antenna, when folded over, is nohigher than the top of the tracks 104, 138. Further, the antenna can besized so that, when folded over, it does not extend beyond the back ofthe housing 102. This can protect the antenna during storage, duringrollover, or when the robot is passing under a low object.

FIG. 1 also illustrates cliff sensors 120, 128 under the camera 124 andIR LEDs 122, 126 on the front of the robot. Cliff sensors 120, 128 canalso be provided at the rear of the robot, particularly if the robot candrive in a reverse direction. In various embodiments, a wall-followingsensor can also be provided on each side of the robot, for example undereach side camera 114 and side IR LEDs 112, 116.

In certain embodiments of the present teachings, the robot can have afront-to-back overall length of about 260 millimeters. The distancebetween the front and rear axles can be about 165 millimeters. Theheight of the robot excluding the antenna can be about 95 millimeters.The height of the robot including the antenna can be about 307millimeters, indicating that embodiments of the antenna can extend about211 millimeters above the robot, although the actual height of theantenna in the illustrated embodiment is greater than 211 millimetersbecause the antenna is slightly recessed below the top track. The widthof the robot can be about 224 millimeters between flipper externalsurfaces and about 204 millimeters between track outer edges.

FIG. 2 is a side view of the embodiment illustrated in FIG. 1,illustrating an exemplary size and shape of the flipper 110 and itsfour-bar linkage 108 where it mounts to the rear axle 142 of the robot100. FIG. 2 also illustrates that in a stowed position, the flipper 110can cover the side camera 114 and IR LEDs 112, 116. A wall-followingsensor, when available on the robot, may also be covered by flipper 110.The present teachings contemplate flippers comprising a necked taper orother accommodation (not shown) to reduce coverage of the cameras and/orwall sensors.

FIG. 3 is a perspective view of an exemplary embodiment of a flipperstructure in accordance with the present teachings. The flipperstructure may comprise, for example, an arm 150, a plurality of legs152, and an attachment base 154. As shown in FIGS. 1 and 2, for example,when the flipper structure is attached to a remote vehicle, such as, forexample, a remote vehicle 100, the flipper 110 may extend longitudinallyalong the side of the remote vehicle 100. The legs 152 and base 154comprise a four-bar linkage which can flex to allow an outer surface ofthe flipper 110 to remain substantially parallel to the robot even whenthe flipper 110 deflects in response to a side-impact force. Flipperstructures and linkages are further described in U.S. patent applicationSer. No. 13/340,957, filed Dec. 30, 2011, for Resilient WheelAssemblies, which is incorporated by reference herein in its entirety.

FIG. 4 illustrates a side perspective view of the robot embodiment ofFIG. 1, with the cover, antenna, let flipper, left wheels, and lefttrack removed to show an interior of the robot. A battery (not visiblein FIG. 4) can be centrally located and housed, for example, between abottom of the robot and battery cover 204. The battery can be, forexample, a 14.8V 5.6 Ah (82.88 Wh) Lithium-ion battery with a PCB, forexample an 8-cell battery. The battery can weigh, for example, about 385grams (13.6 ounces). The present teachings contemplate utilizing anybattery that can provide enough power to maintain the power needs of therobot for at least the desired mission length of about 6-10 hours, andthat is small enough to accommodate the small form factor of the robot.

FIG. 4 also illustrates a mobility board (PCB) 218 located at a forwardposition in the robot 100. The mobility board 218 can control motors(for example, within casing 310 illustrated in FIG. 5) to drive thefront axle 244, and can receive input from sensors such as one or moregyros, accelerometers, sensors for a side-of-shaft magnetic encoder forodometry, temperature sensors for each front wheel drive motor, andpower monitoring electronics. The mobility board 218 can be coupled tocliff sensors 120, 128, which are illustrated on a bottom portion of thefront of the robot housing.

A flipper board (PCB) 202 can be provided on a rear side of the batterycover 204. The flipper board 202 can control a flipper motor and canalso receive input from, for example, temperature sensors monitoring aflipper motor temperature and a temperature of a shell (housing) of therobot. An application board (such as application board 416 in FIG. 8)can be provided above the battery cover 204. The application board canbe seen in cross section in FIGS. 4, 6, and 9, and is illustratedschematically in FIG. 15A and FIG. 15B. The application board 416 can beconnected to the mobility board 218 and the flipper board 202, and alsoto camera PCBs (such as camera PCB 418 in FIG. 8 and 626 in FIG. 12).For example, flexible cables 224 and connectors 230 can be used toconnect the camera PCBs 226, 228 to the application board.

Front axle 244 and rear axle 242 are illustrated exposed in FIG. 4, anddrive gear assembly 222 for the front wheels is partially visible on aside of the mobility board 218. A portion of the flipper clutch 206 isillustrated in FIG. 4 on a side of the flipper board 202, and is furtherdescribed below.

FIG. 5 illustrates a top perspective view of the embodiment of FIG. 1,with the cover, antenna, certain internal elements like printed circuitboards (PCBs) and the battery, left flipper, left wheels, and left trackremoved. Cliff sensors 120, 128 and cliff sensor PCBs 320, 348 can beseen at a front of the housing 102. Behind the cliff sensors 120, 128 isa casing 310 for two front wheel drive motors. The casing 310 alsosupports gear 326A of each of the drive gear assemblies 326 (comprisingdrive gears 326A-326D) for a front wheel. Various embodiments of thepresent teachings can include a right drive gear assembly and a letdrive gear assembly. Each drive gear assembly 326 can be used totranslate motor rotation to a respective front wheel 130 with properspeed reduction, as would be understood by those skilled in the art.

Behind the front wheel drive motor casing 310 is a contoured portion 344of the housing bottom that can be used to support a battery (such asbattery 614 in FIG. 10). In an embodiment, the contours 344 can bearranged to accommodate an 8-cell battery having four cells supported bya bottom of the housing 350. One skilled in the art will understand,however, that the bottom of the housing 350 need not be contoured to thebattery, or can be contoured to accommodate other battery shapes. Thecontours 344 can assist in dissipating heat from the battery, becausethe contours increase a surface area of the housing that can be used forheat dissipation. A wall (610 in FIG. 10) on either side of thecontoured bottom portion of the housing can optionally be provided tohold the battery securely in the housing.

On an outside of each battery-securing wall 610 are the camera, IR LEDs,and wall-following sensors 308. The housing 102 can protrude along theside to provide space for side-located cameras, IR LEDs, wall-followingsensors 308, and their PCBs 328. The housing protrusion preferably canfit within a cavity bounded by the wheels 106, 118, 130, and 136 to thefront and rear (that is, by wheels 106 and 118 on one side of the robot,and by wheels 130 and 136 on another side of the robot), by the track138 on the top and bottom, and/or by a flipper (when in its stowedposition) on the outside. For impact protection, the protrusion can besufficiently low-profile to be protected at least in part by the wheels,track, and flipper if the robot is thrown or dropped.

Behind the contoured bottom portion 344 of the housing is a flippermotor 338 attached by a small gear 306 to a flipper drive gear 340. Theflipper drive gear 340 can include a friction-based slip clutch asdescribed hereinbelow. Referring to FIGS. 6 and 7, in certainembodiments of the present teachings, the flipper drive gear 340includes a slotted cylindrical protrusion 358 (comprising protrusions364 and slots 362) that surrounds the rear axle 242. The slottedcylindrical protrusion 358 can be surrounded by a collar 346 that can betightened by tightener 352 to compress the slotted cylindricalprotrusion 358 to clamp the gear 340 to the rear axle 242, for example,at a predetermined torque corresponding to a slip torque. The slots inthe protrusion 356 can facilitate clamping by the collar, because theyallow the protrusion 358 to shrink around the axle 242. The flipperdrive gear 340 can comprise, for example, brass or another suitablystrong material such as certain metals, plastics, or composites.

In the illustrated exemplary embodiment of FIG. 5, on a side of the rearaxle 302 opposite the flipper drive gear 340 is a side-of-shaft magneticencoder 336 to track a rotational position of the flipper 110. Themagnetic encoder 338 can be connected to a sensor, for example, onflipper board (PCB) 202 (see FIG. 2). For simplicity and space savings,the respective sensors for the flipper position magnetic encoder 338 andan odometry magnetic encoder 350 can be located, for example, adjacentto associated encoders on the flipper board 202 and the mobility board218, respectively. Rear axle 242 can also comprise an offset flatsurface 304, which can engage with flippers 110 to rotate the flippersabout the rear axle 242.

FIG. 8 is a cross sectional view of the robot of FIG. 1 s taken throughthe front axle drive gear 326B and looking toward a front of the robot.Application board 416 is disposed within housing 102 above mobilityboard 218. Front camera PCB 418 is disposed within housing 102 forwardof the application board 416. The front cliff detector PCBs 320, 348 canalso be seen disposed forward of the application board 416 withinhousing 420.

FIG. 9 is a cross sectional view of the robot embodiment of FIG. 1,taken through the front axle 244 and looking toward a rear of the robot.The rear camera 524, camera PCB 512, and IR LEDs 522, 526 are disposedwithin housing 102 rearward of the mobility board 218 and theapplication board 416, which are illustrated in cross section. The frontaxle 244, the drive gears 326B and 326D, the front wheels 118, 130,tracks 104, 138, and fasteners 540 can be seen in cross section. Thefasteners 540 couple the wheels 118, 130 to the front axle 244. In theillustrated exemplary embodiment, a bottom surface of the housing raisesup in the center 542 under the front axle. The antenna mast 132 and itsradio frequency (RF) connector 528 can be seen in cross section, alongwith the RF cable 532 and its connector 544. The RF cable 532 connectsthe antenna (not illustrated) to the radio. An example of the radio 924is illustrated in FIG. 9. In the illustrated embodiment, the antennamast 132 is mounted in a recessed area 534 of the top surface of thehousing 102. This can protect the mounting area of the antenna mast 132from impacts to a top surface of the robot. The mounting area may beless pliable than the mast and therefore more likely to be damaged uponimpact because it cannot bend to absorb forces. If, for example, therobot rolls over, the antenna mast 132 can bend and the recessed area534 can substantially protected the antenna mount from direct impactforces due to its placement in the recess. One skilled in the art willunderstand that the antenna mast 132 need not be mounted in a recessedarea of the housing and can be mounted to a top surface of the housing,within the housing and protruding through an aperture in a top surfaceof the housing, etc.

FIG. 10 is a cross sectional view of the robot of FIG. 1, taken throughthe side cameras 114 and looking toward a rear of the robot. The cameras114, camera PCBs 226, wall-following sensors 612, and wall-followingsensor PCBs 618 can be seen in cross section on each side of the robot.In certain embodiments of the present teachings, the wall-followingsensor PCBs 618 will be connected to mobility board 218. The camera PCBs226 can be connected to the application PCS 416 via, for example,flexible cables 224 extending from the camera PCBs 226 on each side ofthe robot to connectors 230 that are connected to the centrally-locatedapplication board 416. The battery cover 204 can be seen in crosssection under the application board 416, and a cross section of a soundexciter 602 can be seen above the application board. Battery 614 can beprovided below and in contact with battery cover 204. Battery cover 204can be made of an appropriate heat conducting material to conduct heataway from battery 614, and additionally can be made of a material thatcan withstand the heat produced by the battery and the robot in avariety of environmental conditions and for a variety of tasks. Inaddition, battery cover 204 can include contouring or other shaping toaccommodate battery 614 to increase the surface area of contact betweenthe battery 614 and battery cover 204, to better conduct heat from thebattery 614. The present teachings contemplate utilizing a variety ofrechargeable and non-rechargeable power sources in addition to, orinstead of, the illustrated battery 614.

Various embodiments of robot 100 in accordance with the presentteachings can produce sound. Sound can be produced in a number of ways,for example using a conventional small speaker or by the illustratedsound exciter 602. Sound exciter 602 can turn virtually any solid objectinto a speaker by vibrating it at speeds of up to 20,000 cycles persecond (Hz). The solid object preferably has a large, flat surface area.In the illustrated embodiment, a payload expansion port cover (such ascover 140) can serve as the surface vibrated by the sound exciter 602 toproduce sound. However, if the payload expansion port cover is removedto allow attachment of a payload, another suitable surface can beprovided for vibration by the sound exciter 602. A sound exciter can useless energy than a conventional speaker to produce a suitable sound.

FIG. 11 is a cross sectional view of the robot of FIG. 1, taken throughthe rear axle 242 and looking toward a rear of the robot. A crosssection of the rear axle 242, tracks 104, 138, rear wheels 106, 136, andflippers 110 can be seen, as well as inserts 706, 734 and fasteners 708,732 (which can be the same as fasteners 540 shown in FIG. 9), whichcouple the wheels and flippers to the rear axle 242. In certainembodiments, the rear axle 242 does not drive the rear wheels 106, 136and thus the rear wheels can be free to rotate about the rear axle 242.However, the rear axle 242 can drive the flippers 110. The flippers 110can be driven, for example, by engagement of a small offset flat surface304 on each end of the rear axle 242 engaging a complementary offsetflat surface on an insert 706, 734 that attaches to each flipper base ina manner set forth in the disclosure of U.S. patent application Ser. No.13/340,957, filed Dec. 30, 2011, for Resilient Wheel Assemblies, whichis incorporated by reference herein in its entirety.

Magnetic encoder 336 tracks a rotational position of the flippers 110,and is illustrated proximate to the flipper board 202. In addition, theflipper drive gear 340 and its cylindrical protrusion 358 can be seen incross section, along with the collar 346 that can be used to tighten thecylindrical protrusion 358, and therefore the flipper drive gear 340, tothe rear axle 242.

FIG. 12 is a cross sectional view of the robot of FIG. 1, taken througha portion of a right-side drive gear assembly and looking toward a rightside of the robot. The rear axle 242, the front axle 244 and two of thefront wheel drive gears 326A and 326B can be seen. In addition, theflipper board 202, the mobility board 218 and the application board 416can be seen in cross section. The payload expansion port cover 140 atthe top of the robot housing 102 can also fee seen in cross section. Aside camera PCB 226 and a wall-following sensor PCB 618 can be seen,along with a flexible cable 224 connecting at least the camera PCB 226to the application board 416.

FIG. 13 is a cross sectional view of the robot of FIG. 1, taken midwaythrough the robot and looking toward a right side of the robot A drivemotor 902 for the right front wheel 130 can be seen in a locationforward of the battery 614. The flipper drive motor 946, flipper board202, rear axle 242, and rear camera 524 can be seen in cross section ata location rearward of the battery 614. It can be seen by comparing theside cameras 114 illustrated in FIG. 10 to the front and rear cameras124, 524 illustrated in FIG. 13, that the angles of the front and rearcameras in the illustrated embodiment are aimed higher than the sidecameras. For example, as illustrated in FIG. 10, side cameras 114 can beaimed substantially parallel to, for example, the front and rear axles.By comparison, front and rear cameras 124, 524 can be aimed above aplane described by the front and rear axles. Exemplary connections ofthe front camera 124 and rear camera 524 to the application board 416(e.g., via a flexible cables 948, 954 and connectors 950, 952) are shownbelow a forward and a rearward end of the application board.

In the illustrated embodiment, a power ON/OFF switch 938 can be providedrearward of the rear axle 940, along with a charge port 936 and chargeportion PCB assembly 956. One skilled in the art will understand thatthe charge port 936 and power switch 938 can be located in otherlocations on the remote vehicle. In the illustrated exemplaryembodiment, a radio 924 is provided above the application board 416between the rear camera 524 and the sound exciter 602. In theillustrated embodiment, the radio 924 is mounted to the housing 102 viathermal pads 926 that can conduct heat from the radio 924 to the housing102 to help dissipate heat produced by the radio during operation.Forward of the radio is the sound exciter 602, which is located directlyunder the payload expansion port cover and exciter surface 140. Thepayload expansion port cover 140 can be vibrated by sound exciter 602 toproduce sound.

The radio 924 can be, for example, an 802.11 family digital radio, with100 mW transmit power, operating on 2.4 or 4.9 GHz. 802.11 familydigital radios include digital radios that can operate in a variety offrequency ranges, and in embodiments can be capable of maintainingbidirectional data connections to multiple peers at the same time. Inembodiments, the robot 900 can establish and maintain connections up to6 Mbps through radio 924. The radio is connected in a known manner withthe antenna discussed hereinabove.

FIG. 14 is a schematic diagram of an exemplary embodiment of a robotsystem 1000 in accordance with the present teachings. The battery 1002is connected directly or indirectly to the flipper board 1004, themobility board 1006, the application board 1003, and the radio 1010 toprovide component power. A charge port 1012 is connected to chargingcontacts 1014 on the flipper board 1004. The flipper motor 1016 isconnected to the flipper board 1004, as is the power button 1018,temperature sensors 1022, and a flipper position sensor 1020 that readsa magnetic flipper position encoder such as, for example, magneticflipper position encoder 704 or 942. On the mobility board 1006, themotor driver 1024 can send a signal via the flipper board 1004 to theflipper motor 1016 to drive the flipper motor 1016.

The mobility board 1006 can also comprise one or more odometry positionsensors 1026 that read a magnetic odometry encoder, and amicrocontroller 1028 such as, for example, a ATXMEGA microcontroller orsimilar microcontroller or microprocessor to control operations of therobot system. Inputs to the microcontroller 1028 can include a flipperposition from flipper position sensor 1020, temperature information fromtemperature sensors 1022 (e.g., temperature of the housing, each drivemotor, and the flipper motor), power level information from battery1002, and information from such sensors as a gyro 1030 and anaccelerometer 1032. The microprocessor 1028 can also receive data fromcliff sensors 1034 and wall following sensors 1036 (e.g., via auniversal asynchronous universal transmitter (UART)). The microprocessor1028 can be coupled with a memory device, such as an EEPROM or othersimilar memory device, to store data and/or machine-readableinstructions for retrieval and execution by microprocessor 1028. In theillustrated embodiment, a front bump sensor 1038 can also be included toprovide information to microcontroller 1028. Power can be provided tomobility board 1006 from battery 1002 through appropriate powerconnections, and the power can be routed through power regulator 1042for voltage regulation.

The mobility board 1006 is connected to the application board 1008 andcan send power and data thereto through appropriate power and dataconnections. Power sent to the application board 1008 can pass through apower regulator 1040. A power and USB connection 1044 is providedbetween the radio 1010 and the application board 1008. Cameras 1046(e.g., a front camera, rear camera, left side camera, and right sidecamera) can also be connected to the application board 1008. Cameras1046 can be, for example, connected to the application board 1008 via acamera multiplexer (MUX) and LED driver 1048, which can also driveillumination provided for the cameras.

The application board 1008 can also include a USB payload port 1050 thatcan be located under a payload expansion port cover such as the payloadexpansion port cover 140 illustrated in FIGS. 1 and 12. The payload port1050 and a sound exciter 1052 can connect to a power managementintegrated circuit 1054, such as the illustrated PMC circuit. In analternative embodiment, instead of sound exciter 1052, the robot cancomprise an audio system of one or more speakers and one or moremicrophones in position 1052. The illustrated application board 1008also includes a processor 1056 such as the illustrated digital mediaprocessor, for example the illustrated DM3730, including camera capture,memory such as NAND+DDR PoP, connection for an SD memory card, etc. Itwill be appreciated that any appropriate processor can be used in theplace of processor 1056.

FIGS. 15A and 15B provide two exemplary communication PCB diagrams forPCBs that may be used in connection with the embodiments of the presentteachings, illustrating two PCBs for the communications module/card tosupport multiple radio options. A communication PCB illustrated in FIG.15A comprises USB port 1102, PCI-USB bridge 1104, PCI port 1108, andradio 1108. USB port 1102 enables a connection with, for example, theapplication board. Bridge 1104 enables translation between communicationformats, for example between PCI and USB formats. PCI port 1106communicates with radio 1108, which can be any appropriate radio toenable wireless communication, for example, a Ubiquity XR4 radio. Incontrast with FIG. 15A, a communication PCB illustrated in FIG. 15B canutilize a USB connection between USB port 1110 and radio 1116, obviatinga bridge or similar device to communicate with radio 1116.

The use of an additional PCB for radio communication is optional, and inembodiments a USB port can be employed on the application board, so thata separate communication PCB is not needed. If additional radio optionsare desired, the present teachings encompass utilizing the illustratedcommunication PCBs. Alternatively, or additionally, space can bereserved on the application board to accommodate a USB radio. Inembodiments, space is provided on the application board for a relativelylarge USB radio (i.e., larger than a presently typical WiFi radio).

FIG. 16 illustrates a diagram of an exemplary infrared (IR) sensor PCB1200 for wall-following sensors or cliff detection sensors (both ofwhich are typically IR sensors). Analog data 1208 is received by the PCBand sent to, for example, a mobility board 1006 as illustrated in FIG.10. Power 1202 is also received from a power supply, such as battery1002 as illustrated in FIG 14, through an appropriate connection alsoincluding a ground 1204. A power filter and regulator 1210 can beincluded on the PCB 1200, as well as a microcontroller 1212, to controlthe operation of IR illuminators and sensors. In the illustratedexemplary embodiment, the microcontroller 1212 includes an ATtinymicrocontroller. IR sensor PDC 1200 can comprise one or more IR sensorsand associated circuitry. In certain embodiment of the presentteachings, an IR sensor does not saturate in direct sunlight when a bandbass filter is utilized to reject ambient light, and further ambientlight and temperature enable compensation, which may be performed bymicrocontroller 1212. Further, a digital filter such as a digitalinterface can be utilized to lower a noise floor. Thus, using theillustrated IR sensor PCB, the IR sensor PCB can provide a signal thatis filtered to be substantially noise-free. An internal reference canalso be included for diagnostic purposes. In various embodiments, ananalog signal processor is also provided in communication with themicrocontroller. In various embodiments, for cliff sensing and wallfollowing, 2 LEDs operate in a known manner at a modulation rate tosense an object.

FIG. 17 is a diagram of an exemplary camera PCB 1300. Two IR LEDs 1302,1304 are illustrated on either side of digital image sensor 1306, incommunication with a field-effect transistor (FET) 1308. A digital imagesensor 1306 is also provided on the PCB, for example an APTINA CMOSdigital image sensor. Power regulation 1310 can regulate voltageprovided to the PCB via power supply 1312, which can be provided throughan appropriate power connection, including a ground. In embodiments, thecamera PCS 1300 can receive power and ground from the application boardand can send image data to the application board. The camera PCB canalso receive LED and a variety of other control signals from theapplication board and other information, as illustrated.

FIGS. 18A and 18B illustrate an exemplary power system that shows thetop half 1400A and bottom half 1400B of a robot system. A dockingstation 1402 is shown with a charging circuit and an engagement path tosealed contacts 1404 on the robot bottom half 1400B. Power from thecharging circuit of the docking station 1402 can pass through anelectrostatic discharge diode (ESD) protection circuit 1406, a choke1408, a short circuit/reverse polarity protection 1410, an under voltageprotection 1412, and an over voltage protection 1414, to charge thebattery 1418. A power button 1416 can also be connected to the battery1418 to send power to a resistor divider 1420 that divides power betweena microcontroller 1422 (which can be, e.g., an ATMEL microcontroller orother appropriate microprocessor or microcontroller) and a low-dropoutregulator (LDO) 1424 that also channels power to the microcontroller1422. The microcontroller 1422 controls the illustrated motors 1426(e.g., the flipper motor and the front wheel drive motors).

The illustrated robot top half 1400A comprises a radio 1450 and apayload port 1430, as well as the supporting switches 1432, 1438, 1442,1448, chokes 1434, 1440, voltage regulators (LDOs) (such as LDO 1446),and resistors (such as thermistor 1436), which can communicate with therobot bottom half 1400B by appropriate connectors 1428.

FIG. 19 illustrates an exemplary interconnection of robot PCBs such asapplication board 1502 and mobility board 1504, dividing the top half1500A and the bottom half 1500B of the robot for illustrative purposes.The robot bottom half 1500B includes battery contacts 1508 and a battery1510 connected to the mobility board 1504 and to one or more IR boards1512 (e.g., boards for the wall-following and cliff detection IRsensors). A rigid flex connector 1506 connects the mobility board 1504to the application board 1502. An example of a rigid flex connector 1506is flexible cable 224 illustrated in FIG. 2. The application board 1502is connected to the radio 1514 through, for example, a USB connection,and can also be connected to the camera boards illustrated in the tophalf 1500A.

Regarding the relative robot and antenna sizes, from experimentation (orcalculation), a necessary antenna height can he determined that willprevent excessive signal loss, such as fresnel loss, at a desiredmaximum operational distance, in embodiments, an antenna height can bedetermined to maximize a first, second, etc. Fresnel zone determinedfrom the radiation of signals from the antenna, to minimize the effectof out-of-phase signals and other obstacles which may reduce receivedsignal strength of signals from the robot. Additionally, given thedetermined antenna height, the robot should be sized to provide asufficient base for the antenna relative to its size and weight. Asecondary and optional consideration regarding relative robot size isthat the robot should be large enough to allow the antenna to fold flat,for example diagonally, across a top surface of the robot, so that itcan be conveniently and safely stowed. A longer antenna might require analternative configuration either to wrap around the body, or have adesign such as a z-fold or a more complex design to permit the mast tocollapse or fold for stowing, yet stand up during routine operation, inaddition, the robot must include a battery large enough to support thepower draw of the radio over the entire mission duration along with theexpected robot driving profile. The battery size and weight can add tothe size and weight of the robot.

In certain embodiments of the present teachings, sufficient room isprovided for the antenna to fold over and fit within a gap or crushvolume between a top surface of the tracks and a top surface of thehousing, the gap or crush volume being bounded by a plane across the topof the tracks and the top surface of the housing. Certain embodimentsmay not provide enough room for the antenna to fold over and fit insidethe crush volume (i.e., the gap) which can be expected from a 15 ft dropof the robot (which volume may be reduced by compression of the wheels,tracks, and other components upon impact), and depending on how theantenna is folded, the antenna components could be subject to damagefrom pinching or impact from a sufficiently long fall. Accordingly, thepresent teachings contemplate embodiments providing enough room for theantenna to fold over and fit inside the gap between the top of the trackand the top surface of the housing and be protected from damage whichmay result from a long fall.

In various embodiments of the present teachings, the height, length,depth a placement of the wheels, flippers, and tracks (e.g., where thetracks are the tallest feature on the robot other than the antenna)allows the robot to survive drops in random orientations from 5 metersonto concrete. To survive such drops the wheels are used as energyabsorbers and thus all of the features on the robot housing (except forthe bendable, resilient antenna) are recessed below the outline of thewheel, allowing space for the wheels to compress before the housing hitsthe ground.

An exemplary process for robot stair climbing using a remote vehiclesuch as a small unmanned ground vehicle is set forth in U.S. PatentPublication No. 2010/0139995, filed Dec. 9, 2008, titled Mobile RoboticVehicle, the disclosure of which is incorporated herein by reference inits entirety. The disclosed climbing methodology in the '995 publicationapplies to a robot of the size and weight class defined herein onconventional stairs. Conventional stair are defined as having a riserheight of about 7.5″ to about 8.0″.

Operator Control Unit

Embodiments of the present teachings also provide a rugged and waterresistant operator control unit (OCU) that is preferably of a hand-heldsize and can optionally be worn on the user's wrist. Embodiments of theOCU should be daylight readable, preferably backlit for reading atnight, and have a 200-meter radio range to the robot. In variousembodiments, the OCU can be provided with an attachment device so thatthe OCU can be affixed to an operator's wrist or arm, and thus be“wearable”. The OCU preferably does not require users to wear wires orother boxes, so that it is easy to put on and take off. Variousembodiments of the OCU also include a suitable built-in radio forcommunication with one or more associated remote vehicles. The OCUpreferably has a battery life that at least matches that of the robot(s)it is intended to control, for example about 8 hours.

The Exemplary illustrated OCU embodiment has a curved (recessed) backsurface, which helps the OCU accommodate the curve of an operator'sforearm when worn thereon. Elastic straps or other similar attachmentdevices can be used to allow attachment to the operator's arm or anotherobject that operator may wish to attach the device to.

Electronically, various embodiments of the design can be built around amicrocontroller such as Texas Instruments® OMAP 3530 or similarmicrocontroller core, which can include a Gumstix Overo Module or acustom PCB. In an embodiment, the OMAP can tie directly to the OCU's LCDand touch screen interface, and a USB port can be used to interface tothe radio system. In certain embodiments, a spare USB port can beprovided via a waterproof connector, so that the operator can attach/forexample, a USB audio device, such as a headset, or can attach the OCU toa desktop computer to download recorded images or videos. Additionally,the internal battery can be charged, for example, via a separatewaterproof connector, and a sealed power switch can complete theexternal interface of the OCU. The OCU's radio antenna preferably foldsconveniently out of the way for storage, and can be flipped up whenmaximum range is needed.

Certain embodiments of the OCU can include four battery cells that aresplit into two separate strings, allowing them to fit into themechanical structure of the OCU in such a way as to provide theforearm-complementing recess along the back of the OCU mentioned above.

The OCU includes an input device to receive input from an operator. Inembodiments, the input device can be a joystick, keyboard, or othertactile input mechanism. In embodiments, the input device can be, forexample, a touchscreen interface on a display of the OCU, such as an LCDpanel. Combinations of the above are also possible. The presentteachings contemplate employing two conceptual methods for driving therobot: (1) a “Virtual thumbstick” conceptual method; and (2) a “click todrive” conceptual method, for the virtual thumbstick method, across-hair is drawn on the screen by an operator, and touching thescreen in the vicinity of the cross-hair sends instructions to the robotto drive/turn appropriately, in the click-to-drive method, touching thevideo image causes the robot to drive toward the area selected in theimage.

FIGS. 20 and 21 illustrate an exemplary embodiment of a handheldcontroller (OCU) for controlling a robot in accordance with the presentteachings. FIG. 21 including some exemplary measurements in millimeters.The two figures illustrate slightly differing embodiments of the OCU.Housing 1602 supporting a display 1604 and a stowable antenna 1606(illustrated in a stowed state). Housing 1602 also comprises a recess1608, which can accommodate an operator's forearm to support the housing1602 when worn on an operator's forearm. Housing 1602 can also comprisean attachment device, such as straps or other appropriate attachment(see, for example, FIGS. 27-31), to secure the housing 1602 to anoperator's forearm or another object or surface. Display 1604 cancomprise, for example, a liquid crystal display (LCD) screen (e.g., aWVGA 800×480 side LED backlit). A charge connector 1612 and a powerbutton 1610 are also shown in FIG. 16B. In certain embodiments, thepower button 1610 can be pressed to turn the OCU on, can be pressedbriefly to put the OCU in a sleep mode, and can be pressed and held fora predetermined time (e.g., 4 seconds) to turn the OCU completely off.In an exemplary embodiment, embodiment, the OCU is 110 millimeters wideand 156 millimeters long.

FIGS. 22 and 23 illustrate the handheld controllers of FIGS. 20 and 21,with FIG. 22 including an additional exemplary measurement inmillimeters. A USB port 1702 is illustrated on housing 1602, to permit adata/power connection to another appropriate device. In FIG. 22, theexemplary OCU can have a thickness of 37.5 mm, however the thickness canvary in other embodiments of the OCU. Antenna 1606 is illustrated in astate deployed for operation to communicate with a robot system. Display1604 can be, for example, a touch input device to provide commands tothe OCU as well as to display information.

FIG. 24 is a side view of the handheld controller of FIG. 20. FIG. 24illustrates recess 1802 to accommodate, for example, a user's forearmwhen the OCU is worn thereon. Antenna 1608 is illustrated end-on in astowed position.

FIG. 25 is a side view of the handheld controller of FIG. 20, with thehousing illustrated as transparent to permit a view of internalcomponents of the OCU. Battery units 1902, 1904 can be accommodated inportions of the OCU housing which protrude in a rearward direction ofthe OCU housing. In embodiments, the housing can be molded to provideportions which can accommodate batteries and which are formed to sidesof the recess 1802. When two battery compartments are so provided, theweight of the battery units 1902, 1904 can be distributed on either sideof the recess, to balance the OCU when strapped to an arm or otherobject. Also visible in cross-section are a radio 1904, a USB connector1906, a processor 1910, display 1604, a display support 1912, and a mainboard 1914, also discussed below.

FIG. 26 is a top perspective view of an embodiment of the handheldcontroller shown in FIG. 20, with the cover and screen removed. Thebatteries 1902, 1904 can be seen disposed along sides of the OCU. Radio1906 and USB connector 1908 can be provided in the OCU, in between thebattery units 1902, 1904. Processor 1910 can also be provided to controloperation of the OCU, in an exemplary embodiment, the processor 1910 canbe a Gumstix module, though it will be appreciated that any appropriateprocessor can be used in the OCU.

FIG. 27 is a side perspective view of another exemplary embodiment of anOCU that can be attached to an operator's forearm or wrist using one ormore attachment devices. In the illustrated embodiment, straps 2102 andaccommodating buckles 2104 can be provided on the rear of the OCUhousing permit attachment to an operator. The illustrated OCU comprisesa housing having a top portion 2116 and a bottom portion 2118, a display1604 (such as an LCD screen, which can be, e.g., a WVGA 800×480 side LEDbacklit LCD screen), a power button 2110, a charge connector 2108, and aUSB port 2106. Wrist straps 2102 and buckles 2104 can be attached to thebottom portion 2118 of the housing.

FIG. 28 is a side perspective view of the controller of FIG. 27, withthe top portion of the housing removed. Display screen 1004 can be seendisposed within the housing and supported by display support 1914 tosupport an outer portion of the display screen 1604. A batteryprotection board 2206 is illustrated covering each of the battery units1902, 1904 to protect the battery units. The battery protection boards2206 can include a protrusion 2208 which protrudes toward the topportion of the OCU, and which in embodiments can support an innersurface of the top portion of the OCU.

FIG. 29 is a side perspective view of the OCU of FIG. 27, with the topportion of the housing and the display screen removed. Batteries 1902,1904 can be provided along a side surface of each side of the OCUhousing, with at least one of the batteries including a batteryprotection board 2306. Main board (PCS) 1916 is shown disposed along aninner surface of the lower half of the OCU housing, which supportsprocessor 1910 (such as, for example, a Gumstix module) and an SD cardslot 2310. A flexible connector or cable 2316 can be used to connect themain board to at least a display screen.

FIG. 30 is a cross sectional view of the controller of FIG. 27. Strap2102 and buckle 2104 are attached to the lower half of the OCU housingby a fastener 2406. A battery 2102, 2104 can he seen on each side of thehousing, with at least one of the batteries including a batteryprotection board 2206. A radio or radio module 1906 is in a bottomportion of the OCU housing between the batteries 1902, 1904. An SD cardslot 2412, display device 1604, and display board (PCB) 2416 can beprovided in an upper portion of the OCU housing.

FIG. 31 is another cross sectional view of the controller of FIG. 27.Straps 2102 are attached to a lower portion of the OCU housing by strapconnectors 2504 (for example, fastener 2406). A touch panel 2508 can beprovided above display 1604 to enable the OCU to receive inputs. Displayboard (PCB) 2416 is disposed below display 1604 to control operations ofthe display 1604. A flexible connector 2316 can be used to connect thedisplay board 2416 to the main board 1916. Radio or radio module 1906can be disposed in a bottom portion of the housing, along with a USBconnection 2514 to permit a data/power connection with the radio/module1906 through USB connector 2518. Power button 2110 is disposed along asurface of the housing to permit the control of operational states ofthe OCU.

FIG. 32 illustrates an embodiment of an OCU system diagram, illustratingconnections of a charger 2602, batteries 2604, radio 2606 (which can be,for example, a SR71 Radio), a display board (ROB) 2608, and a touchpanel 2610 to the main PCB 2612. Battery protection board 2614communicates with battery connector 2616, which can receive power from acharger jack of charger 2602. Power from the batteries can pass througha power switch 2618 to a power regulation system 2620 for the main PCB2612. Processor 2622 (which can be, in embodiments, a Gumstix Overo Fireprocessor, or other appropriate processor) can receive input from, forexample, an ambient light sensor 2624 and a three-axis accelerometer2626. A vibration motor can optionally be provided comprising a driver2630 and a connector 2628. A backlight LED driver 2632 can also foeprovided drive a backlight for display 2608. Touch panel 2610 canreceive input and communicate the input to processor via an appropriateconnector through a connection, which can optionally include a databuffer to provide smooth transfer of data.

FIG. 33 is a system diagram for an exemplary embodiment of a robotdocking station 2702 including a charger. The docking station 2702 cancomprise power input 2704 to receive power from an external electricalsource which provides received power to smart charger unit 2706. Smartcharger unit 2706 is in communication with charger PCS 2708, whichcontrols charging operation of the docking station 2702. The charger PCBis also in communication with charge pins 2710, through which chargingpower is provided to a robot when the robot is coupled with dockingstation 2702 to charge battery units of the robot.

FIG. 34 is a system diagram for another exemplary embodiment of a robotdocking station and charger. Docking station 2802 can comprise powerinput 2804 to receive power from an external electrical source whichprovides received power to power supplies 2806 and 2810, to providepower to the robot charge port 2808 and the OCU charge port 2812,respectively. Docking station 2802 can thus accommodate both a robotsystem at charge port 2802 and an OCU for the robot system at chargeport 2812, to permit convenient charging of the robot and the OCU at thedocking station 2802.

In certain embodiments of the present teachings, the same type ofprocessor can be used in both the robot and the OCU. The processor ispreferably a low power/high performance processor intended for batterypower, and having a digital signal processor to perform mathematicalcomputation. In certain embodiments, tasks can be broken up by processorand calculations can be simultaneously made on both the robot and theOCU.

Motor Dithering

Certain embodiments of a robot in accordance with the present teachingscan use a Freescale Semiconductor MC33932VW H-Bridge to control one ormore drive motors. Because the maximum PWM frequency for this H-bridge(11 KHz) is in the audible range, reducing the audible component of thedriving PWM signal can be desirable. Reducing the audible component canbe accomplished by randomly varying the PWM frequency slightly, so thatno single frequency carries all of the audible energy generated by themotors.

The robot main control loop runs 128 times per second. Each time throughthe control loop, a PWM dithering function can be called to adjust thefrequency of the PWM signal. The frequency can, for example, be set as acenter frequency, plus or minus a small random percentage. Because thisis done frequently, efficient integer math is used in all calculations.

The center frequency can be chosen, for example, to be 10.4166 KHz,because this is a convenient divisor of the embodiment's selected CPU's8 MHz PWM timer clock just below the 11 KHz H-Bridge maximum. This is768 ticks of the 8 MHz PWM timer A Galois Linear Feedback Shift Registercan be used to generate pseudorandom numbers to adjust the period to therange 752 to 783, which is about plus or minus 2% of 768. For a givenduty cycle, a new PWM comparison value can be chosen based on this newPWM period.

There can be an additional constraint imposed by the H-Bridge that theminimum on or off pulse times should be greater than 10 uS to allow theFETs to switch fully on or off. At 10.4166 KHz, this corresponds to dutycycles below 10% and above 80%. For these cases, instead of ditheringthe PWM period, the PWM comparison value is dithered. A random valuebetween 80 and 120 is chosen (10 uS to 15 uS) for the on or off time,and the PWM period is calculated based on the desired duty cycle.

This process can provide a reduced acoustic signature for stealthoperation and can allow use of a more effect H-or age to provide longerrun times. A more efficient H-bridge can also provide improved thermalcharacteristics which lead to less heat sinking and therefore a lighterrobot, and the ability to operate in higher ambient temperatures, inaddition, dithering PWM frequency and pulse width reduces radiatedemissions.

The remote vehicle embodiments described herein can also includeadditional components that were omitted from the drawings for clarity ofillustration and/or operation. Accordingly, this description is to beconstrued as illustrative only and is for the purpose of teaching thoseskilled in the art the general manner of carrying out the presentteachings. It is to be understood that the various embodiments shown anddescribed herein are to be taken as exemplary. Elements and materials,and arrangements of those elements and materials, may be substituted forthose illustrated and described herein, parts may be reversed, andcertain features of the present teachings may be utilized independently,all as would be apparent to one skilled in the art after having thebenefit of the description herein. Changes may be made in the elementsdescribed herein without departing from the spirit and scope of thepresent teachings and following claims, including their equivalents.

It is to be understood that the particular examples and embodiments setforth herein are non-limiting, and modifications to structure,dimensions, materials, and methodologies may be made without departingfrom the scope of the present teachings.

For the purposes of this specification and appended claims, unlessotherwise indicated, all numbers expressing quantities, percentages orproportions, and other numerical values used in the specification andclaims, are to be understood as being modified in all instances by theterm “about” if they are not already. Accordingly, unless indicated tothe contrary, the numerical parameters set forth in the followingspecification and attached claims are approximations that may varydepending upon the desired properties sought to be obtained by thepresent teachings. At the very least, and not as an attempt to limit theapplication of the doctrine of equivalents to the scope of the claims,each numerical parameter should at least be construed in light of thenumber of reported significant digits and by applying ordinary roundingtechniques.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the present teachings are approximations, thenumerical values set forth in the specific examples are reported asprecisely as possible. Any numerical value, however, inherently containscertain errors necessarily resulting from the standard deviation foundin their respective testing measurements. Moreover, all ranges disclosedherein are to be understood to encompass any and all sub-ranges subsumedtherein.

It is noted that, as used in this specification and the appended claims,the singular forms “a,” “an,” and “the,” and any singular use of anyword, include plural referents unless expressly and unequivocallylimited to one referent. As used herein, the term “include” and itsgrammatical variants are intended to be non-limiting, such thatrecitation of items in a list is not to the exclusion of other likeitems that can be substituted or added to the listed items.

It should be understood that while the present teachings have beendescribed in detail with respect to various exemplary embodimentsthereof, it should not be considered limited to such, as numerousmodifications are possible without departing from the broad scope of theappended claims, including the equivalents they encompass.

What is claimed is:
 1. A mobile robot comprising: a housing having a topsurface, a bottom surface, side surfaces, a front surface and a rearsurface; a battery housed within the housing and including two or morecylindrical cells, the battery resting on the bottom surface of thehousing; a driven support surface movably connected to each side of thehousing and configured to propel the housing in at least a forwarddirection, each driven support surface comprising a flexible tracktrained about a pair of wheels; and a flipper rotatably connected toeach side of the housing rearward of a center of gravity of the housing,the flippers being configured to rotate in a first direction to raise arearward end of the robot and to rotate in a second and oppositedirection to raise a forward end of the robot housing, wherein thebottom surface of the housing is contoured to accommodate a shape of thebattery cells and is configured to conduct heat away from the battery byproviding additional surface area for heat dissipation, the mobile robotfurther comprising at least one drive motor and an H-Bridge to controlthe at least one drive motor, the H-bridge reducing an audible componentof the at least one drive motor sound by randomly varying a pitch wavemodulation (PWM) frequency.
 2. The mobile robot of claim 1, furthercomprising a sound exciter, wherein a portion of the housing top surfacecan be acted on by the sound exciter to emit sound.
 3. The mobile robotof claim 1, wherein the mobile robot weighs less than about 5 pounds. 4.The mobile robot of claim 1, wherein the mobile robot dimensions areless than about 10 inches long and about 9 inches wide and about 4inches high exclusive of an antenna.
 5. The mobile robot of claim 1,further comprising a magnetic flipper position encoder on a rear axle ofthe mobile robot and a flipper printed circuit board (PCB) with a sensorlocated adjacent to the magnetic flipper position encoder to track arotational position of the flippers.
 6. The mobile robot of claim 1,further comprising a magnetic odometry encoder on a front axle of themobile robot and a mobility PCB with a sensor located adjacent to themagnetic odometry encoder to track odometry of the mobile robot.